Memristors have been attracting much attention in recent discussions on the post scaling technology. A memristor is a passive two-terminal element having a resistance changing with the current flowing through the element or the voltage applied to the element. A meraristor has a simple structure in which a resistive switching film of a transition metal oxide, chalcogenide or the like is arranged between an upper electrode and a lower electrode. In particular, a cross-point memristor array in which resistive switching film is arranged between a word line electrode and a bit line electrode and in which memristors are formed at intersections of word lines and bit lines can be easily processed on a CMOS circuit, has scalability and circuit plasticity, and on the basis of such advantages, is expected as a new technology that combines logic with memory.
As an example of a basic circuit component composed of cross-point memristors, a latch circuit including memristors A and B that operate complementerily to each other (nave opposite switch polarities). For example, in a structure in which one electrode of the memristor A and one electrode of the memristor B are connected to the same lead wire, when a positive voltage is applied to the lead wire, one memristor changes to a low resistance state (which may be referred to as “closed” in the description below) and the other memristor changes to a high resistance state (which may be referred to as “open” in the description below). When a negative voltage is applied to the lead wire, on the other hand, one memristor changes to a high resistance state and the other memristor changes to a low resistance state.
To realize memristors having opposite switch polarities in the related art, however, there is a disadvantage that it is required to take measures for wiring in such a manner that a lower electrode of one memristor is wired to an upper electrode of the other memristor, which results in a complex structure.